Casting machine



H. SPIRO CASTING MACHINE May 13, 1930.`

Filed Nov. 2, 1927 5 SheebS--Sheel l H. SPIRO CASTING MACHINE I May 13, 1,930.

Filed NQv. 2, 419g? 5 sheets-sheet 2 lwvvw-GGWY /4 f v s ////////V////,MI\

May 13,l i930. H. sPlRo 1,758,380

.. CASTING MACHINE Filed Nov. 2, 1927 5 Sheets--Sheet` 5 @ya f/ H. sPlRo 1,758,380

CASTING MACHINE Fld Nov. 2, 1927 5 Sheets-Sheet 4 May 13, 1930.

May 13, 1930. H. sPlRo v 1,758,380

CASTINGMACHINE Filed Nov. 2, 1927 5 Sheets-Sheet 5 muur Multum e the like.

Patented lMayV 13, 1930 This invention relates to improvements in 'casting machines, and more especially adental casting machine adapted for casting teeth, plates, bridges, fillings, inlays, inserts, and

Among thefeatures of my inventionis the `provision of a machine adapted to Ause'ilasks of diierent sizes, yWithmeans for centering "such flasks under the headof the machine. f VI also have to provide zaball ai'rrjoint between the compression head of the machine andthe top of the flask so that the'hea'd fits tightly on the top of the iask even though the same is not exactly level.

In Inyimprove'd liask I also provide a lead through the'plasteror investment both above and below the mould cavity so that the Wait may be more easily eliminated therefrom. In 'flasks asl heretofore made there hasbeen a outlet at only onejendv for the escapeof the Wax. The. 'vvaX is ordinarily removed from the investment by immersing the same in lbci ili`ng Water. VVithonly one such'ou'tlet it "vv'as necessary V,to boilY the ,investment for. a F 'conslderable length ottime, and then frequently much of the residueof ythe vvax remained, This V'continued boiling'ot the investment,- which ordinarily is porous and not very' strong, .resulted in the disintegration of the binder on, the surface of thedplaster eX- posed to the action of suchV prolongedboiling, thus vveakeningde'licate structures Within the mould, resulting in rough,. irritating, and poor fitting castings, andlnecessitating `much Waste of gold Ain polishing. .By the use of my invention, in providing tvvo outlets, the

Wax ordinarily may be boiled out in from'one 'to tvvominutes. Y l if Anotherfeatureof my invention is the provision of an air outlet through the bottom of the investment thus permittingthe ainto escapemore readily from lthe mould cavity as the metal enters. This is a greatimprove" ment over those devices in VWhichthe airmust escape through the poresof theinvestmentor plaster. Inzthese older devices, after thevvaX was removed from Vthe mould cavity, the plaster had to be heatedto high degree to attain. the requisite Permitir.- This... k.heating of the plaster dried Vit lout and frequently ren-,

oHIcAGo, ILLINOIS n MACHINE 2, 1.92"?. serial Nel 236,558.

castings made. In the'use of my invention, 'vvith an air outlet at the bottom, it is only necessary to dry the plaster at an evenglow'temperature. It is not necessary to heat it to rdry it outand make it porous, l

Anotherfeature of my invention is the making ofthe outer ring of the flask split orV hinged thus permitting the easy arrangement of `the pattern Within the flask before pouring the plaster, and also'permitting the easy removal of the plaster and casting' after the vcasting operation. a

1 Another feature of my invention isthe provision of an improved sprue former, With-'a tapering thread at the end, fastened intothe base of theplaster model, upon vvhich the vvax pattern is formed. This has the' advantage of uniting the sprue former' solidly tothe case and eliminates the danger of it falling on' in handling or when the plaster is pouredover it. Another `feature of the invention isthe provisionofan adjustable 'mounting for the spru'e former, thus ermitting its adjustment to the desired heig t in the flask. This also permits the removal ofthe plaster model and Wax pattern With the sprue `former attached for the purpose lof carefully covering the patternvvith acoating of the alaster, or painting the same, after Whic when put back "nto the flask it necessarily assumesits or1g1- nal position. This saves timeso that the remainder ofthe plaster may be poured into the flaskbefore it becomes too thick.

Other `featuresand advantages of 'my'.i-nvention' vvill appear more fully as I proceed vvith my speciication. Y,

In that form of device embodying the features of my invention shown in the accompanying drawings, Figure 1 is avievv in -side elevatiomFigs. 2, 8', and Llare vertlcal sectional `vievvs showing the compression headin different positions, Fig.` 5 an enlargedvertical sectional vievv showing the air outletz at the bottom of the'lask, Fig`. 6 is avievvftaken as indicated by the line 6 of Fig.-7F1g.-7 1s 2m enlarged view cfa portion of the compression head, Fig. 8 is a vievv taken as .indicated VYby t l1e lin e. 8pt 1,.Fi'g. 9 1s a viewtaken as indicated kthe linie .9 er nig-1, rig. 1o 10 is a view taken as indicated by the line V1() of Fig. 1, Fig. 11 is a view taken asindicated by the line 11 ofFig. 1, Fig. 12 is a view taken as indicated by the line 12 of Fig. 10, Fig. 13 is aver-tical sectional view taken through one of the burner pipes, Fig. 14 `is a vertical sectional view'showing the rack and pinion adjustment for thelwork table,Figs. 15,16, and 17 are vertical sectional views taken through the flask, Fig. 18 is a top plan view of the flask, and Fig. 19 is a view in sideelevation of the flask showing a portion of the outer ringe hinged.

As shown in the drawingsthe machine comprises 'a suitable base 10 with an upright ,y `llhav'in'g. its upper end bent overas indicated b'yi11a and formed intov a substantially cylindrical tubular guide 12. for the reciprocable compressionhead13. Y

. `The compression; head 13 is carried on the lower end of a shaft- 14 and mounted thereon V:by means "of the' ballfjoint 15 so that the head will makean 'airtight seal on'the topof a flask even though its upper surfacebe not entirely level. Inside the head is preferably provided an asbestos gasketV or washer 13a to `assist in making a tight air seal with the top The shaft 14H is ,reciprocably' Vmounted in theflower endof a sleeve 16 which i" `is provided with rack teeth 16a engaged by of a flask.

' `theiteeth of afgear- 17 on a shaft 18 controlled byan operating handle 19 so that movement ofthe handle 19 willoperate to raise or lower` the sleeve-16 carrying the compression head .The upper. endof the sleeve'16 a sliding airtightfit overa hollow shaft 20. 21 indicates a suitable air pipe forV supplying airto `the port 20a in the shaft 20 which air is supplied' tothe port-"1Min the shaft ing the compressionhead 13.

`As stated before, the shaft 14 is reciprocably mounted in thelower end of the tubular member 16, and above itsupper end the air 1 4 carrypassage throughfthis member 16 is closed by 'ay valve V22 except when the member 14 is slid wupwardly, so that its upper end 14b engages air is shutoff thevalve-.22, until'the head operating inthe groove25.

`the lower end 22aV of the valve22to lift the same and open such air passage. `The mem-1 aber 14 is -normallyfheld inits lower position by meansof the `spiral spring 23 and its sliding movement in the `tubular member e 16 is limited by means ofthe pin 24 having its end VVhenthe `compression head is lowered, the

1 f engages theupperledge of theflask.when,the

shaft-.14 is raised .-relatively to the valve v22 i against the compression of thespring 23-until the valve is opened. As soon as the valve is opened.y airis permitted'to passthroughinto the flask as shown in-Fig. 4.

. `26`indicates1anadjiistable flask supporting table or worksupportmountedin astandard `L27V on then/base 10.- The support carried by a shaft 28 provided with rack teeth 29 engaged by a pinion 30 mounted on a shaft 31 controlled byv aV hand wheel 32. By these means the lwork table may be raised or lowered to any desired height to accommodate the same to the particular flask being used. The table is adapted to be held inany desired y position by means of the dog 33 adapted to be set between the'teeth 34 on the member 28.

I have also provided improved centering means" on the -table 26 operating in conjuncy16, 1927, the upper edge of the cylindrical wall being bent inwardly and downwardly as indicated at 38, with its inner edge bent downwardly to form the inner depending concen- `tric ring 39 lying inside of and parallel with v4the outer wallof the flask. This ring 39 prevents the escape of pressure rfrom the topy of the flask between the investment and the outer wall of the flask as described in the pattent referred to. r i

In the use of the machine, the flask37 is inverted as shown in Fig. 15 on top of a suitable support 40 which carries an adjustable mountingwfor the sprue former 41. Such adjustable mounting comprises two clamps or springs42 on the part 43 sothat the sprue former may be slid upwardly or downwardly but is firmly held at any desired height. The

end o f the sprue former 41 has a tapered thread 44 adapted to be screwed into'the base of the plaster model 45 upon which the wax pattern46 is formed. 47 indicates a waX lead from the model to theV sprueformer, and 48 wax lead` from the model tothe bottom (when the flask is upright as in thecasting process) of the flask. The part 43 is separable from the flask support- 40,

Y. After the parts Vare in position, as shown in Fig. 15, the bottom plate 49 of the flask is put in placeand the investment or plaster 50 poured in. .The yflask is then turned in the upright position, as shown in Fig. 17, the sup-l port 40 removed, the sprue former 41` taken out, and thelwaX melted out by moldat an even,low temperature.

It is to be notedthat one side or portion of the flask 37 is hingedlyattached, as indicated drying the Aby 37 E(see'Figs. 18 and-19),thus permitting easyV arrangementof the pattern within the flask before-pouring theplaster and easy removal of the plaster and castingafter the casting operation. Itis also to be noted that Ilprovide the inner ring`39` in theflask which is hugged by thefinvestmentin shrinking to make an air-tight joint. In providing anairtight oint at this point, it is not necessary to have an air-tight joint between the outer wall 37 and the investment 50. In fact, I provide the inner ring 39 to make the air seal to prevent leakage of air between the invest-ment 50 and the outer wall 37. Since the air seal is made around the ring 39, the outer wall 37 does not have to have an air-tight connection with the outer surface of the investment 50. Because of this construction, I can make a port-ion of the outer wall 37 removable, here shown as 37a, which is hingedly attached.

The center of the table 26 is provided with Y an air outlet 51 carrying within the samev a screen 52 mounted on a spring 53 and above the screen 52 there is preferably mounted a porous disk 53amade of paper, cloth, or the like adapted to be engaged by the outlet flange 54 on the bottom ofthe flask so asto make an airtight joint against the compression of the spring 53. l i

55 indicates a blow torch adapted to be used for melting t-he metal 56 in the flask just before the application yof airpressure. The compression head carries an arm 57 adapted to engage this blow torch and move it out of the way as the head is lowered. The swinging of the blow torch automatically shuts oft the air and gas. .The air and gas pipes of the blow torch, as indicated by 55b andl 55a, are rotatably mounted in the ends of the supply pipes 57a and 57b (see Figs. 10 and 12), so

' that as the blow pip-e is swung out of position the airand gas are automatically shut. ofl'.

The swinging of these pipes closes the portsv 58 and 59. 60 indicates a by-pass so that a small amount of gas will continue toflow through the yblow torch for maintaining a pilot light.

61, 61 indicate burners mounted on the bed 26 for keeping the flask heated. The gas supply to these burners is controlled by shutoff valve 62 with a handle. 62a. lThe gas supply to the burners 61 is adapted to be shutoill automatically when the blow torchjisv swung to Vone side. This is accomplished by forming a latch 63 on the end of the valve handle 62a, said latch adapted to bek engaged by the dog 63a on the blow torch, so that when the blow torch is swung to one side the dog 63a will engage the latch 63 to turnthe valve handle 62EL to shut-o' the gas tothe burners 61. The gas burners ymay be turned on again by depressing the Vlatch 63 to clear the dog 63a. Y

v Means are also yprovided for lholding the compression head in its lowered position. Such means comprise tracks 64 in the sides of the guide 12 and pins 65 carried on the ends of a yoke 66 having its lower end rotatably mounted on the member 14 (see Figs. 6 and 7). In lowering the head, the pins travel through the inclined groove 64a until the springs 67 throw them across to strike the shoulders 6 8.

Upon release, the pins will then be forced up into the notches 69a. Upon again loweringV the head, the pins will clear the shoulder 68 and be free to travel upwardly through the groove 69, thus permitting the head to be raised.

While I have shownV and described certain 'embodiments of my invention, it is to be understood that it is capable of many modifications. Changes, therefore, in theconstruction and arrangement may be made ywit-hout departing from the spirit and scope of the invention disclosed in the appended claims,l

a llask supporting table; anadjustable Vcompression head arranged above the table and centered with respect thereto; a flask for use on said table; and co-operating means on the flask and table for automatically centering the same under the compression head, said means comprising co-operating radial slots and projections adapted to `engage said slots.

2. In a device of the character described; aV

flask supporting table; an air outlet in said 'table having aporous member therein springpressed upwardly;a flask; investment in the flask; a mould cavity in the investment; an outlet flange in the bottom of the flask, adapted to engage with the porous member in the Y outlet in the flask supporting table when the flask is in position; 'and an air outlet communicating from the .mould cavity through the outlet flange in the bottom of the ilask tothe porous member in the air outlet in the flask supporting table.

3. In combination with acasting machine; a flask; means on the machine for supporting the flask; investment in the flask; a mold cavity` in the investment; a sprue opening in the investment to the mold cavity; an air outlet in the investmentleading from the mold cavity; a porous member; and means on the casting machine for holdingthe porous member over the end of the air outlet when the flask is supported on the machine.

.l 4. In a device of the character described a flask-supportingV table; a compression head arranged above the table; a spring-pressed cap at the lower edge of the head adapted to seat on a ilask on. the table as the head is lowered; locking mechanism adapted'to lock the head in lowered position as the head is klowered t-he first time kagainst the tension of thek spring means 'carrying lsaid cap; and meansadapted to releasesaid locking mechanism when theV head is lowered a second time.

In witness whereof, I have hereunto set my hand this 18th day of October, 1927.

HARRY SPIROV.- 

